Improvement in sewing-machines



A. BARTHOLF;

Sewing Machine.

Patented May 17, 1859.

UNITED' STATES PATENT 'O FICE',

ABRAHAM BARTHOLF or NEW YORK, N. Y.

" IMPROVEMENT IN SEWlNG-MACHINES.

Specification forming part of Letters Patent No. 24,000, dated May 17,1859.

To all whom it may concerrb:

Be it known that I, ABRAHAM BARTHOLF, of the city, county, and State ofNew York, have invented a new and useful Improvement 'in SewingMachines;and I do hereby declare effective mode of applying and governing theoperation of a thread-controlling lever, by whichthe needle-thread isdrawnback through the cloth to draw up the loop to complete the stitch,and held back to prevent its getting slack during the first portion ofthe descent of the needle and before the point of the latter enters thecloth.

It also consists in a certain novel arrangement of an adj ustable eye,in combi nation with the thread-controlling lever, for the purpose ofadapting the operation of the thread-controlling lever to sewingdifferent thicknesses of material with the same degree of tension on theneedle-thread, and with the same tightness of stitch. v r

To enable others'skilled in the art to make and use my invention, I willproceed to describe its construction and operation.

A is the base-plate of the machine, upon which the cloth or othermaterial is placed to be sewed, and which supports the principal workingparts of the machine.

B is the needle-arm; G, the rock-shaft to which it is attached; and a athe two center screws between which the rock-shaft C is supported.

D is the thread-controlling lever, arranged to move in planesparallelwith the planes of movement of the needle-arm upona stationaryfulcrum, b, which is represented as being secured in a small standard,E, set-upon the plate A, but which may be attached to any fixed part ofthe machine in a suitable position nearthe needle-arm. The -fulcrum b ofthis lever is at one end of it, and at the other end is the eye a,through which the thread passes, and at a short distance from thefulcrum there is a hole, d, provided in the said lever to receive a pin,e, which projects from one side of the needle-arm, and serves to givethe said lever a movement back and forth or up and down along with theneedle-arm. The length of the lever D is so proportioned and thepositions of the fulcrum b and pin 6 so arranged with regard to themovement of the needle-arm that the eye c of the said lever will movefaster than the needle; but the pin e is allowed 'so much play'in thehole d that the needle-arm, 'in withdrawing the needle from the cloth,does not communicate motion to the lever D till it has commenced to drawup the side of the saidlever, surrounding the fulerum pin b, ,and havingthe`pressure to create the necessary degree of friction produced by aclamping-plate, g, and a screw, h, one end of the said clamping-plateresting against a proj ection, i, on the standard E, and the other endhaving the fulcrum-pin b passing through it and resting against one ofthe friction-washers f, and the screw h passing freely through thestandard E and screwing into the clampingplate g, and having its headhearing against the said standard. By turning the said screw h in theproper direction the clamping-plate is drawn toward the standard E andmade to clamp the lever D and its friction-washers f f between it andsaid standard, and in this way the necessary degree of friction iscreated up on the said lever to hold it in a positively stationarycondition during the firstportion of the t movement of the needle-arm-inthe position in which it was left at the termination of the previousmovement of the n`eedle-arm in the Z. The eye'k, which is stationa'ryduring the operation of the machine, occupies such a po sition that thethread passes through it on its way from the spool F, whose axis isstationary,

to the eye cof the thread-controlling lever D, and that the portion ofthe thread between the eyes kand c always forms a considerable anglewith the portion between the eye 75 and spool F and the portion betweenthe eye c and the needle, and the said wire or bar l is adjustable inthe standard E in such a manner as to cause variations in the differencethat will occur in the length of thread between the said eye k and theneedle-eye in the two extreme positions of the thread-controlling lever,such adjustment being for the purpose of adapting the machine to sewvarious thicknesses of material, as will be more easily explained afterI have more fully described the operation of the threadcontrollinglever, which is as follows: When the needle is in its highest position,or farthest withdrawn from the cloth or other material to be sewed, thelever D occupies the position ary, being so held 'by the friction of thepadsor washers f f until the point of the needle has entered the cloth,as shown in Fig. l in black Outline, the thread being in the meantineheld so tight that the eye of the needle runs along it, and being thusprevented by any possibility kinking round the needle, but when thepoint of the needle has penetrated the cloth the pin e, which has bythis time moved across the hole d to the position shown in black in Fig.1, begins to move the lever D along with the needle-arm, but faster, soas to let the thread slack enough to provide for the formation of theloop and its extension by the shuttle, and hence leaves the threadperfectly slack when the needle has completed its descent. The lattercondition of the needle, needle-arm, and lever D are represented in redOutline, and of the thread in blue dotted Outline. The lever D isstationary in the position represented in Fig. 1 in red Outline by thefriction pads or washers f f till the needle-arm has risen far enoughfor the pin e to have moved back across the hole d, which is not untilthe loop is slipping over the heel oi the shuttle, when the said IeverDis caused to rise or move back along with the needlearm, but at asufficiently faster speed to draw up the whole of the slack of thethread and u pull the stitch tight before the needle has quite completedits ascent, so that as the needle completes its ascent the said levermay draw from the spool the necessary quantity of thread for the nextstitch. i

In applying the thread-controlling lever D without the adjustable eye R,however accurately and perfectly it might be constructed and adjusted,it could only operate with absolute perfection for one thickness ofmaterial, and the object of the adjustable eye R is to adapt it todifferent thicknesses of material and different thcknesses of cloth withequal perfection without the necessity of altering the tension of theneedle-thread. The operation of the adj ustment of the eye isillustrated inFigs. Land 3, in the former of which the eye is set forsewing a moderate thickness of cloth, and in the latter for a muchgreater thickness. In each of the above-mentioned figures thecontrolling-lever D is represented in its two extreme positions, and it,will be seen that-in the position of the eye R represented in Fig. 1the difference in the length of thread in the two positions of the leveris considerably less than it is in the position of the eye R representedin Fig. 2, and hence pro- Vision is not made for drawing up the greaterquantity of thread that is necessary to make the stitch in the thickermateriaL The proper adjustment of the eye R will be ascertained by thethread being just drawn tight when, in the lowest position of the leverD, the thickest part of the shuttle is passing through the loop. If thethread is not tightened at this stage of the operation, the eye R isshifted to make the thread form less acute angles at the eyes c R, andif it should be drawn so tight as to draw off more 'thread from thespool F or through the eye c, the eye R must be set to. make the thread'form more acute angles at c R. i

I am aware that levers moved wholly or in part by the needle-arm orneedle-carrier have been applied to sewing-machines to effect the sameresult as the lever D-viz., the drawing back of the thread through thecloth without drawing back the needle'a distance equal to the wholelength of the thread that was protruded through the cloth-but suchlevers have been either allowed to let the thread slack againimmediately after drawing it back through the cloth, or have beencontrolled by springs or spring-latches to hold back the thread duringthe first part of the descent or return of the needle, which devices arenot only less reliable, but more costly than my contrivance forgoverning the action of the lever. In view of such applications of alever I cannot of course claim, broadly, the lever D, operated by theneedle-arm or needle-carrier; but

What I claim as my invention, and desire to secure by Letters Patent,is-

1. Applying the said lever to work on a fixed fulcrum, in combinationwith a frictioni clamp which, though it permits the said lever to bemoved by and with the needle-arm or needle-carrier during a portion ofthe movement of the latter in either direction, for the purpose ofdr'awing back the thread through the cloth and completing the stitch,and letting it slack again to formtheloop of a succeeding stitch, holdsthe said lever in a positively stationary condition during the firstpart of the movement of the said arm Or carrier in either direetion, andso prevents the 'thread getting V slaek: till the needle has entered theeloth, and

prevents it being drawn up through the eloth till the heel of theshuttle has arrived at the i loop, substantially as herein described.

2. lreombination with the thread-controlling lever eonstructed andapplied as specified, and operated, as described, bythe needle-arm orneedle-earrier, the statioary eye R, made adjustable relatively to thesaid lever, substantially as and for the purpose herein set forth. r I IABRAHAM BARTHOLF.

Witnesses:

WM. TUSOH, MICH. HUGHES.

